interface_panel.c

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/*
 * $Id: interface_panel.c 38743 2011-07-26 19:47:56Z campbellbarton $
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * Contributor(s): Blender Foundation, 2003-2009 full recode.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/* a full doc with API notes can be found in bf-blender/trunk/blender/doc/guides/interface_API.txt */
 
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "MEM_guardedalloc.h"

#include "PIL_time.h"

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "DNA_userdef_types.h"

#include "BKE_context.h"
#include "BKE_screen.h"

#include "BIF_gl.h"
#include "BIF_glutil.h"

#include "WM_api.h"
#include "WM_types.h"

#include "ED_screen.h"

#include "UI_interface.h"

#include "interface_intern.h"

/*********************** defines and structs ************************/

#define ANIMATION_TIME          0.30
#define ANIMATION_INTERVAL      0.02

#define PNL_LAST_ADDED          1
#define PNL_ACTIVE                      2
#define PNL_WAS_ACTIVE          4
#define PNL_ANIM_ALIGN          8
#define PNL_NEW_ADDED           16
#define PNL_FIRST                       32

typedef enum uiHandlePanelState {
        PANEL_STATE_DRAG,
        PANEL_STATE_DRAG_SCALE,
        PANEL_STATE_WAIT_UNTAB,
        PANEL_STATE_ANIMATION,
        PANEL_STATE_EXIT
} uiHandlePanelState;

typedef struct uiHandlePanelData {
        uiHandlePanelState state;

        /* animation */
        wmTimer *animtimer;
        double starttime;

        /* dragging */
        int startx, starty;
        int startofsx, startofsy;
        int startsizex, startsizey;
} uiHandlePanelData;

static void panel_activate_state(const bContext *C, Panel *pa, uiHandlePanelState state);

/*********************** space specific code ************************/
/* temporary code to remove all sbuts stuff from panel code         */

static int panel_aligned(ScrArea *sa, ARegion *ar)
{
        if(sa->spacetype==SPACE_BUTS && ar->regiontype == RGN_TYPE_WINDOW) {
                SpaceButs *sbuts= sa->spacedata.first;
                return sbuts->align;
        }
        else if(sa->spacetype==SPACE_USERPREF && ar->regiontype == RGN_TYPE_WINDOW)
                return BUT_VERTICAL;
        else if(sa->spacetype==SPACE_FILE && ar->regiontype == RGN_TYPE_CHANNELS)
                return BUT_VERTICAL;
        else if(sa->spacetype==SPACE_IMAGE && ar->regiontype == RGN_TYPE_PREVIEW)
                return BUT_VERTICAL; 
        else if(ELEM3(ar->regiontype, RGN_TYPE_UI, RGN_TYPE_TOOLS, RGN_TYPE_TOOL_PROPS))
                return BUT_VERTICAL;
        
        return 0;
}

static int panels_re_align(ScrArea *sa, ARegion *ar, Panel **r_pa)
{
        Panel *pa;
        int active= 0;

        *r_pa= NULL;

        if(sa->spacetype==SPACE_BUTS && ar->regiontype == RGN_TYPE_WINDOW) {
                SpaceButs *sbuts= sa->spacedata.first;

                if(sbuts->align)
                        if(sbuts->re_align || sbuts->mainbo!=sbuts->mainb)
                                return 1;
        }
        else if(ar->regiontype==RGN_TYPE_UI)
                return 1;
        else if(sa->spacetype==SPACE_IMAGE && ar->regiontype == RGN_TYPE_PREVIEW)
                return 1;
        else if(sa->spacetype==SPACE_FILE && ar->regiontype == RGN_TYPE_CHANNELS)
                return 1;

        /* in case panel is added or disappears */
        for(pa=ar->panels.first; pa; pa=pa->next) {
                if((pa->runtime_flag & PNL_WAS_ACTIVE) && !(pa->runtime_flag & PNL_ACTIVE))
                        return 1;
                if(!(pa->runtime_flag & PNL_WAS_ACTIVE) && (pa->runtime_flag & PNL_ACTIVE))
                        return 1;
                if(pa->activedata)
                        active= 1;
        }

        /* in case we need to do an animation (size changes) */
        for(pa=ar->panels.first; pa; pa=pa->next) {
                if(pa->runtime_flag & PNL_ANIM_ALIGN) {
                        if(!active)
                                *r_pa= pa;
                        return 1;
                }
        }
        
        return 0;
}

/****************************** panels ******************************/

static void ui_panel_copy_offset(Panel *pa, Panel *papar)
{
        /* with respect to sizes... papar is parent */

        pa->ofsx= papar->ofsx;
        pa->ofsy= papar->ofsy + papar->sizey-pa->sizey;
}

Panel *uiBeginPanel(ScrArea *sa, ARegion *ar, uiBlock *block, PanelType *pt, int *open)
{
        uiStyle *style= U.uistyles.first;
        Panel *pa, *patab, *palast, *panext;
        char *drawname= pt->label;
        char *idname= pt->idname;
        char *tabname= pt->idname;
        char *hookname= NULL;
        int newpanel;
        int align= panel_aligned(sa, ar);
        
        /* check if Panel exists, then use that one */
        for(pa=ar->panels.first; pa; pa=pa->next)
                if(strncmp(pa->panelname, idname, UI_MAX_NAME_STR)==0)
                        if(strncmp(pa->tabname, tabname, UI_MAX_NAME_STR)==0)
                                break;
        
        newpanel= (pa == NULL);

        if(!newpanel) {
                pa->type= pt;
        }
        else {
                /* new panel */
                pa= MEM_callocN(sizeof(Panel), "new panel");
                pa->type= pt;
                BLI_strncpy(pa->panelname, idname, UI_MAX_NAME_STR);
                BLI_strncpy(pa->tabname, tabname, UI_MAX_NAME_STR);

                if(pt->flag & PNL_DEFAULT_CLOSED) {
                        if(align == BUT_VERTICAL)
                                pa->flag |= PNL_CLOSEDY;
                        else
                                pa->flag |= PNL_CLOSEDX;
                }
        
                pa->ofsx= 0;
                pa->ofsy= style->panelouter;
                pa->sizex= 0;
                pa->sizey= 0;
                pa->runtime_flag |= PNL_NEW_ADDED;

                BLI_addtail(&ar->panels, pa);
                
                /* make new Panel tabbed? */
                if(hookname) {
                        for(patab= ar->panels.first; patab; patab= patab->next) {
                                if((patab->runtime_flag & PNL_ACTIVE) && patab->paneltab==NULL) {
                                        if(strncmp(hookname, patab->panelname, UI_MAX_NAME_STR)==0) {
                                                if(strncmp(tabname, patab->tabname, UI_MAX_NAME_STR)==0) {
                                                        pa->paneltab= patab;
                                                        ui_panel_copy_offset(pa, patab);
                                                        break;
                                                }
                                        }
                                }
                        } 
                }
        }

        BLI_strncpy(pa->drawname, drawname, UI_MAX_NAME_STR);

        /* if a new panel is added, we insert it right after the panel
         * that was last added. this way new panels are inserted in the
         * right place between versions */
        for(palast=ar->panels.first; palast; palast=palast->next)
                if(palast->runtime_flag & PNL_LAST_ADDED)
                        break;
        
        if(newpanel) {
                pa->sortorder= (palast)? palast->sortorder+1: 0;

                for(panext=ar->panels.first; panext; panext=panext->next)
                        if(panext != pa && panext->sortorder >= pa->sortorder)
                                panext->sortorder++;
        }

        if(palast)
                palast->runtime_flag &= ~PNL_LAST_ADDED;

        /* assign to block */
        block->panel= pa;
        pa->runtime_flag |= PNL_ACTIVE|PNL_LAST_ADDED;

        *open= 0;

        if(pa->paneltab) return pa;
        if(pa->flag & PNL_CLOSED) return pa;

        *open= 1;
        
        return pa;
}

void uiEndPanel(uiBlock *block, int width, int height)
{
        Panel *pa= block->panel;

        if(pa->runtime_flag & PNL_NEW_ADDED) {
                pa->runtime_flag &= ~PNL_NEW_ADDED;
                pa->sizex= width;
                pa->sizey= height;
        }
        else {
                /* check if we need to do an animation */
                if(!ELEM(width, 0, pa->sizex) || !ELEM(height, 0, pa->sizey)) {
                        pa->runtime_flag |= PNL_ANIM_ALIGN;
                        if(height != 0)
                                pa->ofsy += pa->sizey-height;
                }

                /* update width/height if non-zero */
                if(width != 0)
                        pa->sizex= width;
                if(height != 0)
                        pa->sizey= height;
        }
}

static void ui_offset_panel_block(uiBlock *block)
{
        uiStyle *style= U.uistyles.first;
        uiBut *but;
        int ofsy;

        /* compute bounds and offset */
        ui_bounds_block(block);

        ofsy= block->panel->sizey - style->panelspace;

        for(but= block->buttons.first; but; but=but->next) {
                but->y1 += ofsy;
                but->y2 += ofsy;
        }

        block->maxx= block->panel->sizex;
        block->maxy= block->panel->sizey;
        block->minx= block->miny= 0.0;
}

/**************************** drawing *******************************/

/* extern used by previewrender */
#if 0 /*UNUSED 2.5*/
static void uiPanelPush(uiBlock *block)
{
        glPushMatrix(); 

        if(block->panel)
                glTranslatef((float)block->panel->ofsx, (float)block->panel->ofsy, 0.0);
}

static void uiPanelPop(uiBlock *UNUSED(block))
{
        glPopMatrix();
}
#endif

/* triangle 'icon' for panel header */
/* NOTE - this seems to be only used for hiding nodes now */
void UI_DrawTriIcon(float x, float y, char dir)
{
        if(dir=='h') {
                ui_draw_anti_tria( x-3, y-5, x-3, y+5, x+7,y );
        }
        else if(dir=='t') {
                ui_draw_anti_tria( x-5, y-7, x+5, y-7, x, y+3); 
        }
        else { /* 'v' = vertical, down */
                ui_draw_anti_tria( x-5, y+3, x+5, y+3, x, y-7); 
        }
}

/* triangle 'icon' inside rect */
static void ui_draw_tria_rect(rctf *rect, char dir)
{
        if(dir=='h') {
                float half= 0.5f*(rect->ymax - rect->ymin);
                ui_draw_anti_tria(rect->xmin, rect->ymin, rect->xmin, rect->ymax, rect->xmax, rect->ymin+half);
        }
        else {
                float half= 0.5f*(rect->xmax - rect->xmin);
                ui_draw_anti_tria(rect->xmin, rect->ymax, rect->xmax, rect->ymax, rect->xmin+half, rect->ymin);
        }
}

static void ui_draw_anti_x(float x1, float y1, float x2, float y2)
{

        /* set antialias line */
        glEnable(GL_LINE_SMOOTH);
        glEnable(GL_BLEND);

        glLineWidth(2.0);
        
        fdrawline(x1, y1, x2, y2);
        fdrawline(x1, y2, x2, y1);
        
        glLineWidth(1.0);
        
        glDisable(GL_LINE_SMOOTH);
        glDisable(GL_BLEND);
        
}

/* x 'icon' for panel header */
static void ui_draw_x_icon(float x, float y)
{

        ui_draw_anti_x(x, y, x+9.375f, y+9.375f);

}

#define PNL_ICON        UI_UNIT_X  /* could be UI_UNIT_Y too */

static void ui_draw_panel_scalewidget(rcti *rect)
{
        float xmin, xmax, dx;
        float ymin, ymax, dy;
        
        xmin= rect->xmax-PNL_HEADER+2;
        xmax= rect->xmax-3;
        ymin= rect->ymin+3;
        ymax= rect->ymin+PNL_HEADER-2;
                
        dx= 0.5f*(xmax-xmin);
        dy= 0.5f*(ymax-ymin);
        
        glEnable(GL_BLEND);
        glColor4ub(255, 255, 255, 50);
        fdrawline(xmin, ymin, xmax, ymax);
        fdrawline(xmin+dx, ymin, xmax, ymax-dy);
        
        glColor4ub(0, 0, 0, 50);
        fdrawline(xmin, ymin+1, xmax, ymax+1);
        fdrawline(xmin+dx, ymin+1, xmax, ymax-dy+1);
        glDisable(GL_BLEND);
}

static void ui_draw_panel_dragwidget(rctf *rect)
{
        float xmin, xmax, dx;
        float ymin, ymax, dy;
        
        xmin= rect->xmin;
        xmax= rect->xmax;
        ymin= rect->ymin;
        ymax= rect->ymax;
        
        dx= 0.333f*(xmax-xmin);
        dy= 0.333f*(ymax-ymin);
        
        glEnable(GL_BLEND);
        glColor4ub(255, 255, 255, 50);
        fdrawline(xmin, ymax, xmax, ymin);
        fdrawline(xmin+dx, ymax, xmax, ymin+dy);
        fdrawline(xmin+2*dx, ymax, xmax, ymin+2*dy);
        
        glColor4ub(0, 0, 0, 50);
        fdrawline(xmin, ymax+1, xmax, ymin+1);
        fdrawline(xmin+dx, ymax+1, xmax, ymin+dy+1);
        fdrawline(xmin+2*dx, ymax+1, xmax, ymin+2*dy+1);
        glDisable(GL_BLEND);
}


static void ui_draw_aligned_panel_header(uiStyle *style, uiBlock *block, rcti *rect, char dir)
{
        Panel *panel= block->panel;
        rcti hrect;
        int  pnl_icons;
        char *activename= panel->drawname[0]?panel->drawname:panel->panelname;
        
        /* + 0.001f to avoid flirting with float inaccuracy */
        if(panel->control & UI_PNL_CLOSE) pnl_icons=(panel->labelofs+2*PNL_ICON+5)/block->aspect + 0.001f;
        else pnl_icons= (panel->labelofs+PNL_ICON+5)/block->aspect + 0.001f;
        
        /* active tab */
        /* draw text label */
        UI_ThemeColor(TH_TITLE);
        
        hrect= *rect;
        if(dir == 'h') {
                hrect.xmin= rect->xmin+pnl_icons;
                uiStyleFontDraw(&style->paneltitle, &hrect, activename);
        }
        else {
                /* ignore 'pnl_icons', otherwise the text gets offset horizontally 
                 * + 0.001f to avoid flirting with float inaccuracy
                 */
                hrect.xmin= rect->xmin + (PNL_ICON+5)/block->aspect + 0.001f;
                uiStyleFontDrawRotated(&style->paneltitle, &hrect, activename);
        }
}

static void rectf_scale(rctf *rect, float scale)
{
        float centx= 0.5f*(rect->xmin+rect->xmax);
        float centy= 0.5f*(rect->ymin+rect->ymax);
        float sizex= 0.5f*scale*(rect->xmax - rect->xmin);
        float sizey= 0.5f*scale*(rect->ymax - rect->ymin);
        
        rect->xmin= centx - sizex;
        rect->xmax= centx + sizex;
        rect->ymin= centy - sizey;
        rect->ymax= centy + sizey;
}

/* panel integrated in buttonswindow, tool/property lists etc */
void ui_draw_aligned_panel(uiStyle *style, uiBlock *block, rcti *rect)
{
        Panel *panel= block->panel;
        rcti headrect;
        rctf itemrect;
        int ofsx;
        
        if(panel->paneltab) return;
        if(panel->type && (panel->type->flag & PNL_NO_HEADER)) return;

        /* calculate header rect */
        /* + 0.001f to prevent flicker due to float inaccuracy */
        headrect= *rect;
        headrect.ymin= headrect.ymax;
        headrect.ymax= headrect.ymin + floor(PNL_HEADER/block->aspect + 0.001f);
        
        if(!(panel->runtime_flag & PNL_FIRST)) {
                float minx= rect->xmin+5.0f/block->aspect;
                float maxx= rect->xmax-5.0f/block->aspect;
                float y= headrect.ymax;
                
                glEnable(GL_BLEND);
                glColor4f(0.0f, 0.0f, 0.0f, 0.5f);
                fdrawline(minx, y+1, maxx, y+1);
                glColor4f(1.0f, 1.0f, 1.0f, 0.25f);
                fdrawline(minx, y, maxx, y);
                glDisable(GL_BLEND);
        }
        
        /* horizontal title */
        if(!(panel->flag & PNL_CLOSEDX)) {
                ui_draw_aligned_panel_header(style, block, &headrect, 'h');
                
                /* itemrect smaller */  
                itemrect.xmax= headrect.xmax - 5.0f/block->aspect;
                itemrect.xmin= itemrect.xmax - (headrect.ymax-headrect.ymin);
                itemrect.ymin= headrect.ymin;
                itemrect.ymax= headrect.ymax;
                rectf_scale(&itemrect, 0.8f);
                ui_draw_panel_dragwidget(&itemrect);
        }
        
        /* if the panel is minimized vertically:
                * (------)
                */
        if(panel->flag & PNL_CLOSEDY) {
                
        }
        else if(panel->flag & PNL_CLOSEDX) {
                /* draw vertical title */
                ui_draw_aligned_panel_header(style, block, &headrect, 'v');
        }
        /* an open panel */
        else {
                
                /* in some occasions, draw a border */
                if(panel->flag & PNL_SELECT) {
                        if(panel->control & UI_PNL_SOLID) uiSetRoundBox(15);
                        else uiSetRoundBox(3);
                        
                        UI_ThemeColorShade(TH_BACK, -120);
                        uiRoundRect(0.5f + rect->xmin, 0.5f + rect->ymin, 0.5f + rect->xmax, 0.5f + headrect.ymax+1, 8);
                }
                
                if(panel->control & UI_PNL_SCALE)
                        ui_draw_panel_scalewidget(rect);
        }
        
        /* draw optional close icon */
        
        ofsx= 6;
        if(panel->control & UI_PNL_CLOSE) {
                
                UI_ThemeColor(TH_TEXT);
                ui_draw_x_icon(rect->xmin+2+ofsx, rect->ymax+2);
                ofsx= 22;
        }
        
        /* draw collapse icon */
        UI_ThemeColor(TH_TEXT);
        
        /* itemrect smaller */  
        itemrect.xmin= headrect.xmin + 5.0f/block->aspect;
        itemrect.xmax= itemrect.xmin + (headrect.ymax-headrect.ymin);
        itemrect.ymin= headrect.ymin;
        itemrect.ymax= headrect.ymax;
        
        rectf_scale(&itemrect, 0.5f);
        
        if(panel->flag & PNL_CLOSEDY)
                ui_draw_tria_rect(&itemrect, 'h');
        else if(panel->flag & PNL_CLOSEDX)
                ui_draw_tria_rect(&itemrect, 'h');
        else
                ui_draw_tria_rect(&itemrect, 'v');

        (void)ofsx;
}

/************************** panel alignment *************************/

static int get_panel_header(Panel *pa)
{
        if(pa->type && (pa->type->flag & PNL_NO_HEADER))
                return 0;

        return PNL_HEADER;
}

static int get_panel_size_y(uiStyle *style, Panel *pa)
{
        if(pa->type && (pa->type->flag & PNL_NO_HEADER))
                return pa->sizey;

        return PNL_HEADER + pa->sizey + style->panelouter;
}

/* this function is needed because uiBlock and Panel itself dont
change sizey or location when closed */
static int get_panel_real_ofsy(Panel *pa)
{
        if(pa->flag & PNL_CLOSEDY) return pa->ofsy+pa->sizey;
        else if(pa->paneltab && (pa->paneltab->flag & PNL_CLOSEDY)) return pa->ofsy+pa->sizey;
        else if(pa->paneltab) return pa->paneltab->ofsy;
        else return pa->ofsy;
}

static int get_panel_real_ofsx(Panel *pa)
{
        if(pa->flag & PNL_CLOSEDX) return pa->ofsx+get_panel_header(pa);
        else if(pa->paneltab && (pa->paneltab->flag & PNL_CLOSEDX)) return pa->ofsx+get_panel_header(pa);
        else return pa->ofsx+pa->sizex;
}

typedef struct PanelSort {
        Panel *pa, *orig;
} PanelSort;

/* note about sorting;
   the sortorder has a lower value for new panels being added.
   however, that only works to insert a single panel, when more new panels get
   added the coordinates of existing panels and the previously stored to-be-insterted
   panels do not match for sorting */

static int find_leftmost_panel(const void *a1, const void *a2)
{
        const PanelSort *ps1=a1, *ps2=a2;
        
        if(ps1->pa->ofsx > ps2->pa->ofsx) return 1;
        else if(ps1->pa->ofsx < ps2->pa->ofsx) return -1;
        else if(ps1->pa->sortorder > ps2->pa->sortorder) return 1;
        else if(ps1->pa->sortorder < ps2->pa->sortorder) return -1;

        return 0;
}


static int find_highest_panel(const void *a1, const void *a2)
{
        const PanelSort *ps1=a1, *ps2=a2;
        
        /* stick uppermost header-less panels to the top of the region -
         * prevent them from being sorted */
        if (ps1->pa->sortorder < ps2->pa->sortorder && ps1->pa->type->flag & PNL_NO_HEADER) return -1;
        
        if(ps1->pa->ofsy+ps1->pa->sizey < ps2->pa->ofsy+ps2->pa->sizey) return 1;
        else if(ps1->pa->ofsy+ps1->pa->sizey > ps2->pa->ofsy+ps2->pa->sizey) return -1;
        else if(ps1->pa->sortorder > ps2->pa->sortorder) return 1;
        else if(ps1->pa->sortorder < ps2->pa->sortorder) return -1;
        
        return 0;
}

static int compare_panel(const void *a1, const void *a2)
{
        const PanelSort *ps1=a1, *ps2=a2;
        
        if(ps1->pa->sortorder > ps2->pa->sortorder) return 1;
        else if(ps1->pa->sortorder < ps2->pa->sortorder) return -1;
        
        return 0;
}

/* this doesnt draw */
/* returns 1 when it did something */
static int uiAlignPanelStep(ScrArea *sa, ARegion *ar, float fac, int drag)
{
        uiStyle *style= U.uistyles.first;
        Panel *pa;
        PanelSort *ps, *panelsort, *psnext;
        int a, tot=0, done;
        int align= panel_aligned(sa, ar);
        
        /* count active, not tabbed panels */
        for(pa= ar->panels.first; pa; pa= pa->next)
                if((pa->runtime_flag & PNL_ACTIVE) && pa->paneltab==NULL)
                        tot++;

        if(tot==0) return 0;

        /* extra; change close direction? */
        for(pa= ar->panels.first; pa; pa= pa->next) {
                if((pa->runtime_flag & PNL_ACTIVE) && pa->paneltab==NULL) {
                        if((pa->flag & PNL_CLOSEDX) && (align==BUT_VERTICAL))
                                pa->flag ^= PNL_CLOSED;
                        else if((pa->flag & PNL_CLOSEDY) && (align==BUT_HORIZONTAL))
                                pa->flag ^= PNL_CLOSED;
                }
        }

        /* sort panels */
        panelsort= MEM_callocN(tot*sizeof(PanelSort), "panelsort");
        
        ps= panelsort;
        for(pa= ar->panels.first; pa; pa= pa->next) {
                if((pa->runtime_flag & PNL_ACTIVE) && pa->paneltab==NULL) {
                        ps->pa= MEM_dupallocN(pa);
                        ps->orig= pa;
                        ps++;
                }
        }
        
        if(drag) {
                /* while we are dragging, we sort on location and update sortorder */
                if(align==BUT_VERTICAL) 
                        qsort(panelsort, tot, sizeof(PanelSort), find_highest_panel);
                else
                        qsort(panelsort, tot, sizeof(PanelSort), find_leftmost_panel);

                for(ps=panelsort, a=0; a<tot; a++, ps++)
                        ps->orig->sortorder= a;
        }
        else
                /* otherwise use sortorder */
                qsort(panelsort, tot, sizeof(PanelSort), compare_panel);
        
        /* no smart other default start loc! this keeps switching f5/f6/etc compatible */
        ps= panelsort;
        ps->pa->ofsx= 0;
        ps->pa->ofsy= -get_panel_size_y(style, ps->pa);

        for(a=0; a<tot-1; a++, ps++) {
                psnext= ps+1;
        
                if(align==BUT_VERTICAL) {
                        psnext->pa->ofsx= ps->pa->ofsx;
                        psnext->pa->ofsy= get_panel_real_ofsy(ps->pa) - get_panel_size_y(style, psnext->pa);
                }
                else {
                        psnext->pa->ofsx= get_panel_real_ofsx(ps->pa);
                        psnext->pa->ofsy= ps->pa->ofsy + get_panel_size_y(style, ps->pa) - get_panel_size_y(style, psnext->pa);
                }
        }
        
        /* we interpolate */
        done= 0;
        ps= panelsort;
        for(a=0; a<tot; a++, ps++) {
                if((ps->pa->flag & PNL_SELECT)==0) {
                        if((ps->orig->ofsx != ps->pa->ofsx) || (ps->orig->ofsy != ps->pa->ofsy)) {
                                ps->orig->ofsx= floorf(0.5f + fac*(float)ps->pa->ofsx + (1.0f-fac)*(float)ps->orig->ofsx);
                                ps->orig->ofsy= floorf(0.5f + fac*(float)ps->pa->ofsy + (1.0f-fac)*(float)ps->orig->ofsy);
                                done= 1;
                        }
                }
        }

        /* copy locations to tabs */
        for(pa= ar->panels.first; pa; pa= pa->next)
                if(pa->paneltab && (pa->runtime_flag & PNL_ACTIVE))
                        ui_panel_copy_offset(pa, pa->paneltab);

        /* free panelsort array */
        for(ps= panelsort, a=0; a<tot; a++, ps++)
                MEM_freeN(ps->pa);
        MEM_freeN(panelsort);
        
        return done;
}


static void ui_do_animate(const bContext *C, Panel *panel)
{
        uiHandlePanelData *data= panel->activedata;
        ScrArea *sa= CTX_wm_area(C);
        ARegion *ar= CTX_wm_region(C);
        float fac;

        fac= (PIL_check_seconds_timer()-data->starttime)/ANIMATION_TIME;
        fac= sqrt(fac);
        fac= MIN2(fac, 1.0f);

        /* for max 1 second, interpolate positions */
        if(uiAlignPanelStep(sa, ar, fac, 0))
                ED_region_tag_redraw(ar);
        else
                fac= 1.0f;

        if(fac >= 1.0f) {
                panel_activate_state(C, panel, PANEL_STATE_EXIT);
                return;
        }
}

void uiBeginPanels(const bContext *UNUSED(C), ARegion *ar)
{
        Panel *pa;
  
          /* set all panels as inactive, so that at the end we know
         * which ones were used */
        for(pa=ar->panels.first; pa; pa=pa->next) {
                if(pa->runtime_flag & PNL_ACTIVE)
                        pa->runtime_flag= PNL_WAS_ACTIVE;
                else
                        pa->runtime_flag= 0;
        }
}

/* only draws blocks with panels */
void uiEndPanels(const bContext *C, ARegion *ar)
{
        ScrArea *sa= CTX_wm_area(C);
        uiBlock *block;
        Panel *panot, *panew, *patest, *pa, *firstpa;
        
        /* offset contents */
        for(block= ar->uiblocks.first; block; block= block->next)
                if(block->active && block->panel)
                        ui_offset_panel_block(block);

        /* consistency; are panels not made, whilst they have tabs */
        for(panot= ar->panels.first; panot; panot= panot->next) {
                if((panot->runtime_flag & PNL_ACTIVE)==0) { // not made

                        for(panew= ar->panels.first; panew; panew= panew->next) {
                                if((panew->runtime_flag & PNL_ACTIVE)) {
                                        if(panew->paneltab==panot) { // panew is tab in notmade pa
                                                break;
                                        }
                                }
                        }
                        /* now panew can become the new parent, check all other tabs */
                        if(panew) {
                                for(patest= ar->panels.first; patest; patest= patest->next) {
                                        if(patest->paneltab == panot) {
                                                patest->paneltab= panew;
                                        }
                                }
                                panot->paneltab= panew;
                                panew->paneltab= NULL;
                                ED_region_tag_redraw(ar); // the buttons panew were not made
                        }
                }       
        }

        /* re-align, possibly with animation */
        if(panels_re_align(sa, ar, &pa)) {
                if(pa)
                        panel_activate_state(C, pa, PANEL_STATE_ANIMATION);
                else
                        uiAlignPanelStep(sa, ar, 1.0, 0);
        }

        /* tag first panel */
        firstpa= NULL;
        for(block= ar->uiblocks.first; block; block=block->next)
                if(block->active && block->panel)
                        if(!firstpa || block->panel->sortorder < firstpa->sortorder)
                                firstpa= block->panel;
        
        if(firstpa)
                firstpa->runtime_flag |= PNL_FIRST;

        UI_ThemeClearColor(TH_BACK);
        
        /* draw panels, selected on top */
        for(block= ar->uiblocks.first; block; block=block->next) {
                if(block->active && block->panel && !(block->panel->flag & PNL_SELECT)) {
                        uiDrawBlock(C, block);
                }
        }

        for(block= ar->uiblocks.first; block; block=block->next) {
                if(block->active && block->panel && (block->panel->flag & PNL_SELECT)) {
                        uiDrawBlock(C, block);
                }
        }
}

/* ------------ panel merging ---------------- */

static void check_panel_overlap(ARegion *ar, Panel *panel)
{
        Panel *pa;

        /* also called with panel==NULL for clear */
        
        for(pa=ar->panels.first; pa; pa=pa->next) {
                pa->flag &= ~PNL_OVERLAP;
                if(panel && (pa != panel)) {
                        if(pa->paneltab==NULL && (pa->runtime_flag & PNL_ACTIVE)) {
                                float safex= 0.2, safey= 0.2;
                                
                                if(pa->flag & PNL_CLOSEDX) safex= 0.05;
                                else if(pa->flag & PNL_CLOSEDY) safey= 0.05;
                                else if(panel->flag & PNL_CLOSEDX) safex= 0.05;
                                else if(panel->flag & PNL_CLOSEDY) safey= 0.05;
                                
                                if(pa->ofsx > panel->ofsx- safex*panel->sizex)
                                if(pa->ofsx+pa->sizex < panel->ofsx+ (1.0f+safex)*panel->sizex)
                                if(pa->ofsy > panel->ofsy- safey*panel->sizey)
                                if(pa->ofsy+pa->sizey < panel->ofsy+ (1.0f+safey)*panel->sizey)
                                        pa->flag |= PNL_OVERLAP;
                        }
                }
        }
}

/************************ panel dragging ****************************/

static void ui_do_drag(const bContext *C, wmEvent *event, Panel *panel)
{
        uiHandlePanelData *data= panel->activedata;
        ScrArea *sa= CTX_wm_area(C);
        ARegion *ar= CTX_wm_region(C);
        short align= panel_aligned(sa, ar), dx=0, dy=0;
        
        /* first clip for window, no dragging outside */
        if(!BLI_in_rcti(&ar->winrct, event->x, event->y))
                return;

        dx= (event->x-data->startx) & ~(PNL_GRID-1);
        dy= (event->y-data->starty) & ~(PNL_GRID-1);

        dx *= (float)(ar->v2d.cur.xmax - ar->v2d.cur.xmin)/(float)(ar->winrct.xmax - ar->winrct.xmin);
        dy *= (float)(ar->v2d.cur.ymax - ar->v2d.cur.ymin)/(float)(ar->winrct.ymax - ar->winrct.ymin);
        
        if(data->state == PANEL_STATE_DRAG_SCALE) {
                panel->sizex = MAX2(data->startsizex+dx, UI_PANEL_MINX);
                
                if(data->startsizey-dy < UI_PANEL_MINY)
                        dy= -UI_PANEL_MINY+data->startsizey;

                panel->sizey= data->startsizey-dy;
                panel->ofsy= data->startofsy+dy;
        }
        else {
                /* reset the panel snapping, to allow dragging away from snapped edges */
                panel->snap = PNL_SNAP_NONE;
                
                panel->ofsx = data->startofsx+dx;
                panel->ofsy = data->startofsy+dy;
                check_panel_overlap(ar, panel);
                
                if(align) uiAlignPanelStep(sa, ar, 0.2, 1);
        }

        ED_region_tag_redraw(ar);
}

/******************* region level panel interaction *****************/


/* this function is supposed to call general window drawing too */
/* also it supposes a block has panel, and isnt a menu */
static void ui_handle_panel_header(const bContext *C, uiBlock *block, int mx, int my, int event)
{
        ScrArea *sa= CTX_wm_area(C);
        ARegion *ar= CTX_wm_region(C);
        Panel *pa;
        int align= panel_aligned(sa, ar), button= 0;

        /* mouse coordinates in panel space! */
        
        /* XXX weak code, currently it assumes layout style for location of widgets */
        
        /* check open/collapsed button */
        if(event==RETKEY)
                button= 1;
        else if(event==AKEY)
                button= 1;
        else if(block->panel->flag & PNL_CLOSEDX) {
                if(my >= block->maxy) button= 1;
        }
        else if(block->panel->control & UI_PNL_CLOSE) {
                /* whole of header can be used to collapse panel (except top-right corner) */
                if(mx <= block->maxx-8-PNL_ICON) button= 2;
                //else if(mx <= block->minx+10+2*PNL_ICON+2) button= 1;
        }
        else if(mx <= block->maxx-PNL_ICON-12) {
                button= 1;
        }
        
        if(button) {
                if(button==2) { // close
                        ED_region_tag_redraw(ar);
                }
                else {  // collapse
                        if(block->panel->flag & PNL_CLOSED) {
                                block->panel->flag &= ~PNL_CLOSED;
                                /* snap back up so full panel aligns with screen edge */
                                if (block->panel->snap & PNL_SNAP_BOTTOM) 
                                        block->panel->ofsy= 0;
                        }
                        else if(align==BUT_HORIZONTAL) {
                                block->panel->flag |= PNL_CLOSEDX;
                        }
                        else {
                                /* snap down to bottom screen edge*/
                                block->panel->flag |= PNL_CLOSEDY;
                                if (block->panel->snap & PNL_SNAP_BOTTOM) 
                                        block->panel->ofsy= -block->panel->sizey;
                        }
                        
                        for(pa= ar->panels.first; pa; pa= pa->next) {
                                if(pa->paneltab==block->panel) {
                                        if(block->panel->flag & PNL_CLOSED) pa->flag |= PNL_CLOSED;
                                        else pa->flag &= ~PNL_CLOSED;
                                }
                        }
                }

                if(align)
                        panel_activate_state(C, block->panel, PANEL_STATE_ANIMATION);
                else
                        ED_region_tag_redraw(ar);
        }
        else if(mx <= (block->maxx-PNL_ICON-12)+PNL_ICON+2) {
                panel_activate_state(C, block->panel, PANEL_STATE_DRAG);
        }
}

/* XXX should become modal keymap */
/* AKey is opening/closing panels, independent of button state now */

int ui_handler_panel_region(bContext *C, wmEvent *event)
{
        ARegion *ar= CTX_wm_region(C);
        uiBlock *block;
        Panel *pa;
        int retval, mx, my, inside_header= 0, inside_scale= 0, inside;

        retval= WM_UI_HANDLER_CONTINUE;
        for(block=ar->uiblocks.last; block; block=block->prev) {
                mx= event->x;
                my= event->y;
                ui_window_to_block(ar, block, &mx, &my);

                /* check if inside boundbox */
                inside= 0;
                pa= block->panel;

                if(!pa || pa->paneltab!=NULL)
                        continue;
                if(pa->type && pa->type->flag & PNL_NO_HEADER) // XXX - accessed freed panels when scripts reload, need to fix.
                        continue;

                if(block->minx <= mx && block->maxx >= mx)
                        if(block->miny <= my && block->maxy+PNL_HEADER >= my)
                                inside= 1;
                
                if(inside && event->val==KM_PRESS) {
                        if(event->type == AKEY && !ELEM4(1, event->ctrl, event->oskey, event->shift, event->alt)) {
                                
                                if(pa->flag & PNL_CLOSEDY) {
                                        if((block->maxy <= my) && (block->maxy+PNL_HEADER >= my))
                                                ui_handle_panel_header(C, block, mx, my, event->type);
                                }
                                else
                                        ui_handle_panel_header(C, block, mx, my, event->type);
                                
                                continue;
                        }
                }
                
                /* on active button, do not handle panels */
                if(ui_button_is_active(ar))
                        continue;
                
                if(inside) {
                        /* clicked at panel header? */
                        if(pa->flag & PNL_CLOSEDX) {
                                if(block->minx <= mx && block->minx+PNL_HEADER >= mx) 
                                        inside_header= 1;
                        }
                        else if((block->maxy <= my) && (block->maxy+PNL_HEADER >= my)) {
                                inside_header= 1;
                        }
                        else if(pa->control & UI_PNL_SCALE) {
                                if(block->maxx-PNL_HEADER <= mx)
                                        if(block->miny+PNL_HEADER >= my)
                                                inside_scale= 1;
                        }

                        if(event->val==KM_PRESS) {
                                /* open close on header */
                                if(ELEM(event->type, RETKEY, PADENTER)) {
                                        if(inside_header) {
                                                ui_handle_panel_header(C, block, mx, my, RETKEY);
                                                break;
                                        }
                                }
                                else if(event->type == LEFTMOUSE) {
                                        if(inside_header) {
                                                ui_handle_panel_header(C, block, mx, my, 0);
                                                break;
                                        }
                                        else if(inside_scale && !(pa->flag & PNL_CLOSED)) {
                                                panel_activate_state(C, pa, PANEL_STATE_DRAG_SCALE);
                                                break;
                                        }
                                }
                                else if(event->type == ESCKEY) {
                                        /*XXX 2.50 if(block->handler) {
                                                rem_blockhandler(sa, block->handler);
                                                ED_region_tag_redraw(ar);
                                                retval= WM_UI_HANDLER_BREAK;
                                        }*/
                                }
                                else if(event->type==PADPLUSKEY || event->type==PADMINUS) {
#if 0 // XXX make float panel exception?
                                        int zoom=0;
                                
                                        /* if panel is closed, only zoom if mouse is over the header */
                                        if (pa->flag & (PNL_CLOSEDX|PNL_CLOSEDY)) {
                                                if (inside_header)
                                                        zoom=1;
                                        }
                                        else
                                                zoom=1;

                                        if(zoom) {
                                                ScrArea *sa= CTX_wm_area(C);
                                                SpaceLink *sl= sa->spacedata.first;

                                                if(sa->spacetype!=SPACE_BUTS) {
                                                        if(!(pa->control & UI_PNL_SCALE)) {
                                                                if(event->type==PADPLUSKEY) sl->blockscale+= 0.1;
                                                                else sl->blockscale-= 0.1;
                                                                CLAMP(sl->blockscale, 0.6, 1.0);

                                                                ED_region_tag_redraw(ar);
                                                                retval= WM_UI_HANDLER_BREAK;
                                                        }                                               
                                                }
                                        }
#endif
                                }
                        }
                }
        }

        return retval;
}

/**************** window level modal panel interaction **************/

/* note, this is modal handler and should not swallow events for animation */
static int ui_handler_panel(bContext *C, wmEvent *event, void *userdata)
{
        Panel *panel= userdata;
        uiHandlePanelData *data= panel->activedata;

        /* verify if we can stop */
        if(event->type == LEFTMOUSE && event->val!=KM_PRESS) {
                ScrArea *sa= CTX_wm_area(C);
                ARegion *ar= CTX_wm_region(C);
                int align= panel_aligned(sa, ar);

                if(align)
                        panel_activate_state(C, panel, PANEL_STATE_ANIMATION);
                else
                        panel_activate_state(C, panel, PANEL_STATE_EXIT);
        }
        else if(event->type == MOUSEMOVE) {
                if(data->state == PANEL_STATE_DRAG)
                        ui_do_drag(C, event, panel);
        }
        else if(event->type == TIMER && event->customdata == data->animtimer) {
                if(data->state == PANEL_STATE_ANIMATION)
                        ui_do_animate(C, panel);
                else if(data->state == PANEL_STATE_DRAG)
                        ui_do_drag(C, event, panel);
        }

        data= panel->activedata;

        if(data && data->state == PANEL_STATE_ANIMATION)
                return WM_UI_HANDLER_CONTINUE;
        else
                return WM_UI_HANDLER_BREAK;
}

static void ui_handler_remove_panel(bContext *C, void *userdata)
{
        Panel *pa= userdata;

        panel_activate_state(C, pa, PANEL_STATE_EXIT);
}

static void panel_activate_state(const bContext *C, Panel *pa, uiHandlePanelState state)
{
        uiHandlePanelData *data= pa->activedata;
        wmWindow *win= CTX_wm_window(C);
        ARegion *ar= CTX_wm_region(C);
        
        if(data && data->state == state)
                return;

        if(state == PANEL_STATE_EXIT || state == PANEL_STATE_ANIMATION) {
                if(data && data->state != PANEL_STATE_ANIMATION) {
                        /* XXX:
                         *      - the panel tabbing function call below (test_add_new_tabs()) has been commented out
                         *        "It is too easy to do by accident when reordering panels, is very hard to control and use, and has no real benefit." - BillRey
                         * Aligorith, 2009Sep
                         */
                        //test_add_new_tabs(ar);   // also copies locations of tabs in dragged panel
                        check_panel_overlap(ar, NULL);  // clears
                }

                pa->flag &= ~PNL_SELECT;
        }
        else
                pa->flag |= PNL_SELECT;

        if(data && data->animtimer) {
                WM_event_remove_timer(CTX_wm_manager(C), win, data->animtimer);
                data->animtimer= NULL;
        }

        if(state == PANEL_STATE_EXIT) {
                MEM_freeN(data);
                pa->activedata= NULL;

                WM_event_remove_ui_handler(&win->modalhandlers, ui_handler_panel, ui_handler_remove_panel, pa, 0);
        }
        else {
                if(!data) {
                        data= MEM_callocN(sizeof(uiHandlePanelData), "uiHandlePanelData");
                        pa->activedata= data;

                        WM_event_add_ui_handler(C, &win->modalhandlers, ui_handler_panel, ui_handler_remove_panel, pa);
                }

                if(ELEM(state, PANEL_STATE_ANIMATION, PANEL_STATE_DRAG))
                        data->animtimer= WM_event_add_timer(CTX_wm_manager(C), win, TIMER, ANIMATION_INTERVAL);

                data->state= state;
                data->startx= win->eventstate->x;
                data->starty= win->eventstate->y;
                data->startofsx= pa->ofsx;
                data->startofsy= pa->ofsy;
                data->startsizex= pa->sizex;
                data->startsizey= pa->sizey;
                data->starttime= PIL_check_seconds_timer();
        }

        ED_region_tag_redraw(ar);

        /* XXX exception handling, 3d window preview panel */
        /* if(block->drawextra==BIF_view3d_previewdraw)
                BIF_view3d_previewrender_clear(curarea);*/
        
        /* XXX exception handling, 3d window preview panel */
        /* if(block->drawextra==BIF_view3d_previewdraw)
                BIF_view3d_previewrender_signal(curarea, PR_DISPRECT);
        else if(strcmp(block->name, "image_panel_preview")==0)
                image_preview_event(2); */
}